A resistive random-access memory (RRAM) is one kind of non-volatile memory. Since the resistive random-access memories have higher accessing speeds, simpler structures, non-volatile properties and higher reliability, the manufacturers of the memories pay much attention to the development of the resistive random-access memories. Moreover, as the semiconducting technology is increasingly developed, the 3D resistive memory with a high-density design becomes a critical research issue.
In the resistive memory, each memory cell comprises a resistive memory element. The resistive memory element may be programmed to different storage states. For example, the storage states include a set state and a reset state.
For example, when a set voltage is applied to the two terminals of the resistive memory element, the resistive memory element is in the set state corresponding to a low resistance value. Whereas, when a reset voltage is applied to the two terminals of the resistive memory element, the resistive memory element is in the reset state corresponding to a high resistance value.
For example, a resistive memory element is disclosed in U.S. Pat. No. 10,050,156. The resistive memory element a P-type layer, a tunneling structure and an N-type layer. If the bias voltage between the P-type layer and the N-type layer is higher than the reset voltage, the resistive memory element is in the reset state. Whereas, if the bias voltage between the P-type layer and the N-type layer is lower than the reset voltage, the resistive memory element is in the set state.